Metallurgical process



l and Gnonsn B; FRANKroRrER, citizens of the .United States,

Y UNITED STATES PATENT orriou.

HENRY B. HOVLAND, OF DULUTH, AND

To all whomtt may concern:

Be it known that we, HENRY B. HOVLAND residing at Duluth, St. Louiscounty, and Minneapolis, Hennepin county, Minnesota, respectively, haveinvented certain new and useful Im rove'ments in MetallurgicalProcesses; an we do hereby declarej the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to metallurgical processes, and it comprises moreparticularly a process wherein metal sulfid concentrates or analogousmaterials, comprising more or less gangue are 'first roasted to oxidizesubstantially all the metal of the metal sulfid and to loosen andseparate gangue from the metalliferous particlesof the concentrates, theroasted concentrates are then resulfidized for the purpose of dislodgingany-remaining gangue, the resulting metal sulfid is then subjected totreatment by'a suitable flotation process whereby substantially puremetal sulfid concentrates are obtained.

Sulfid concentrates of metals such as copper, lead, silver, zinc,nickel, cobalt, manganese, iron,- etc., as heretofore obtained greateror less proortions of gangue materials which it has een customary toremove by smelting processes involving the use of purifying fluxes andexpensive high temperature treatment.

We regard the present process as of particular importance in connectionwith the treatment of copper sulfid concentrates obtained by any method.The application of all the process will therefore be described asapplied to copper sulfid concentrates for purposes of illustration, itbeing understood, however, that the invention is not limited to copperconcentrates, but extends to metal sulfid concentrates and analogousnietalliferous materials in general, including Briefly described, thepresent process,

' when applied to copper sulfid concentrates,

consists in subjecting such concentrates obtained by any suitableconcentrating method to a roasting operation. This roasting operationmay be carried on at temperatures METALLURGICAL PROCESSQ snoaen B;raanxroarn t, or. MINNEAPOLIS, unmnso'ra; sun rmxronrmr. assrenon :0 sunHOVLAND. f

Patented Mar. 30, 1920.

Serial a. 794,940. Renewed Octoberi), 1916. Serial 110. 127,307." I a inthe neighborhood of 350 -to" 'l0()" (l, or even higher in someinstances,ibut at no time should the temperature be sufliciently high tobring about fusion of. the materials bemg roasted. After the roastingoperation is sufliciently completefthe resulting roast-- ing materialscontaining the .copper largely in oxidized condition may, if-necessary,be ground to a suitable degreeof fineness'in preparation for the nextstep in the process. By oxidized condition isjmeant the usual chemicalforms resulting from the roasting operation, such as oxids, sulfates andthe like of the metals treated.

The finely divided roasted material is now mixed or pulped with a ratherdilute solution of an acid, suchas sulfuric or sulfurous acid, and themixture or pulp is subjected to the action of a sulfidizing agent, suchas hydrogen sulfid, which may be introduced into the pulp either as agas or in aqueous solution. The strength of the acid solution employedmay vary considerably but a content of from one to five per cent. ofsulfuric acid is found in practice to be a convenient and effectivestrength. The quantity of acid solution used naturally varies with thecopper content of the material treated.

In this sulfidizing operation, the oxidized copper is converted eitherentirely or merely superficially into copper sulfid; and this conversion is accompanied by a mechanical loosening or dislodgment of anygangue materials still adhering to. the metalliferous particles.

The acidified sulfidized mixture is then threated by any suitableflotation process in order to obtain substantially pure sulfidconcentrates; for example, the sulfidized pulp may be agitated with asuitable quantity of an oil, such as kerosene, or other equivalentmaterial, the pulped ore being.) thoroughly aerated during the agitationwith the oil, whereupon the metalliferous sulfid particles float andcollect at the surface of the flotation liquor where they may .beskimmed oil in any suitable way. The

manner just described are substantially pure copper sulfid beingpractically free from gangue materials of any kind.

While our .new process is articularly adapted to the treatment of s fidconcentrates, the process can nevertheless be apwell adapted totreatment by the present- "process; as is also copper matte. Orescarrying values partly as sulfids and partly in oxidized condition mayalso be treated with advantage in the manner described. It is to beunderstood that the materials treated may contain more than one of themetals speclfidized without In applying our process to the recovery ofmetals like zinc, manganese, etc., whose sulfids are soluble in sulfuricor other strong acids, the sulfidizing operation is carried out inneutral or alkaline solution. urally also, other specific details of theprocess as described for copper must be modified as a rule to someextent according to the particular metal sought.

In some instances it is advantageous to modify the sulfidizing step.somewhatby first bringing the metal to be recovered into solution afterthe first 'roast, then separatingthe solution from the 'gangue more orless completely as by decantation, and then sulfidizing and floating.This procedure gives a separation of the metal values from the bulk ofthe gangue prior to sulfidizing. If desired, the dissolved copper may besuldecanting the solution from the gangue.

Various sulfidizing agents may be em-.

'- ployed in the forego' g process, and they may be variously app ed. a

The copper or other metal may .be recovered from theflotationconcentrates by any suitable method; and-the flotationtailings, particularly where a preliminary concentration of the ore hasbeen effected, may be treated for the recovery of precious or othermetals still contained therein, as by the cyanid process.

What we claim is:

1. The process of-extractingmetal values from metalliferous materialwhich comprises roasting such material in order to oxidize the metalsought, convertin such oxidized metal at leastpartl into sull d, andsubjecting the resulting su fidized material to treatment by flotation.

2. The process of extracting metal values Natfrom material carrying ametal sulfid which comprises roastingsuch material in order to oxidizethe metal, sulfidizing the roasted material in the presence ofan acid,and concentrating the sulfidized material by flotation.

3. The process of extracting metal values -which comprises roasting amaterial carrying copper sulfid in order to oxidize the co per,sulfidizing the oxidized copper in the presence of an acid, andconcentrating copper sulfid by flotation.

4. The process of extracting metal values from metalliferous materialwhich comprises roasting such material to convert the metal valuesvtherein to oxidized condition, dissolving the metal values of'the roast,precipitating the dissolved metal values as sulfid, and concentratingthe sulfidized material h flotation. a

-5. he process of extracting 00 per from material containing the same, w1011 comprises roasting such material to convert the copper intooxidized condition, dissolving the oxidized copper of the roast,precipitating the copper as sulfid, and concentrating the copper sulfidby flotation.

6. The process of treating material for the extraction of values, whichcomprises subjecting the materials to be treated to the-action ofsulfurous acid, adding a sulfidizing agent, and recovering values byflotation.

7 The process of extracting metal values from material containing thesame, which comprises roasting such material to oxidize the metalsought, subjecting such roasted material to the action of a solvent forthe metal to be'extracted, recipitating the dissolved metal as sulfi inthe gangue, and separatingsaid sul sociated gangue by flotation.

tpresence of d from as- 8. The process of treating material, whichcomprises subjecting the material to a roasting operation, to the actionofsulfurous acid, to the action of a sulfidizing agent, and to aflotation o eration.

9. The process 0 treating metalliferous material, which comprisessubjecting said material to the action of sulfurous acid, in-

' troducing a sulfidizing agent, and separating the values.

10. The process of extracting metal values which comprises roasting thematerial carrying copper sulfid in order to oxidize the copper,sulfidizing the oxidized co per, and concentrating copper sulfid byflotation. t

11. The process of treatin metalliferous material for the extraction 0values, which comprises subjecting the material to be treated to theaction of sulfurous acid, addin a sulfidizing a ant, and se arating vaues from associatet l 12. The process of treating cupriferous gangue byI otation.

and separating the values.

comprises subjecting the material to be treatedto the action ofsulfurous acid, adding a precipitating agent, and separating theprecipitated values from associate gangue by flotation.

14. The process of treating metalliferous material which comprisessubjecting said material to the action of sulfurous acid, introducing asulfidizing agent to precipitate the metal values in the presence ofgangue,

15. The method of treating materials for the recovery of metals whichcomprises subjecting pulp to the effect of products of reaction betweena soluble sulfid and a metal sulfite.

16. The method of treating materials for the recovery of metals whichcomprises sub-- jecting pulp to the effect of products of reactionsbetween sulfurous acid and a sulfid.

17. The method of recovering metal values from material containing thesame which comprises subjectin said material to the action of sulfurousacid, separating solution from gangue more or less completely,

then sulfidizing in presence of the bulk of the gangue, and separatingvalues from gangue by flotation.

18. The method of recovering copper from ores carrying copper inoxidized condition comprising subjecting such ore to the action ofsulfurous acid, precipitating copper values in the presence of gangue,and separatin precipitated copper values from associate gangue byflotation.

19. The. process of treating ores carrying values partly as sulfid andpartly in oxidized condition comprising subjecting such ores to theaction of sulfurous acid, to the action of a sulfidizing agent, and to aflotation operation.

20. he process of treating ores carrying values partly as sulfid andpartly in oxi- IIGSSGS.

dized condition comprising subjecting such ore to the action ofsulfurou's acid, to the action of a sulfidizing agent, and floatingartificial sulfids so produced in the presence of native sulfids of theoriginal ore.

21. The process of treating ores carrying values partly as sulfid andpartly in oxidized condition comprising subjecting such ore to theaction of sulfurous' acid, separat ing solution from gangue more or lesscompletely, sulfidizing' in presenceof the bulk of the gangue andfloating artificial sulfids so produced in the presence of nativesulfids of the original ore.

22. The process of treating ores carrying values partly as sulfid andpartly in oxidized condition comprising subjecting such ore to theaction of sulfurous acid, separating solution'from gangue more or lesscompletely, precipitating values in the presence of the bulk of thegangue and floating precipitates so produced in the presence of nativesulfids of the ori inal ore.

23. The process 0 treating ores which comprises subjecting the same to apreliminary treatment to loosen and separate the gangue from themetalliferous particles, and then subjecting the thus treated ore to theaction of solvent, precipitating the metal values by a sulfidizing agentand then concentrating the sulfidized material by flotation.

24.. The process of treating ores which comprises subjecting the sameafter concentration to a preliminary treatment to loosen and separatethe gangue from the metalliferous particles, and then subjecting thethus treated ore to the actionof solvent, precipitating the metal valuesby a sulfidizing agent and then concentrating the sulfidized materialbyflotation.

In testimony whereof we hereunto afiix our signatures in the presence oftwo wit- HENRY B. HOVLAND. GEORGE B. FRANKFORTER.

Witnesses:

'R. F. STEWARD, E. O. HI'LDEBRAN

